Flights have been disrupted since Friday at Heathrow, Europe's busiest airport, which has seen long lines and stranded passengers camping out on its terminal floors.

Heathrow says it has spent millions improving its winter resilience since the airport was virtually shut down by snow for several days in December 2010. But it says low visibility means it must leave bigger gaps between planes, triggering delays and cancelations.

Forty percent of flights were canceled at Charles de Gaulle and Orly airports in Paris.

In Munich, which saw 13 centimeters (more than 5 inches) of snow overnight, another 200 flights were cancelled, and long delays were expected at both airports.

In northern Germany, slick roads outside Berlin caused a stretch of a major highway to be closed down for the Monday morning commute, and the high-speed train that runs through Brussels from Paris to Germany was experiencing long delays.

British domestic trains and Eurostar services from France and Belgium to London also were disrupted, and hundreds of schools across Britain were closed.